PTM(4)

📦 version 11.0, in nixpkgs unstable

okay so bestie, welcome to PTM(4) — the Kernel Interfaces Manual page for the pseudo-terminal multiplexor device. It's literally the backstage pass to /dev/ptm, and we're gonna go through it together, no cap. 💅✨

✨ NAME ✨

ptm — pseudo-terminal multiplexor device 🎀

🦋 SYNOPSIS 🦋

yep, this is the whole vibe:

pseudo-device pty

💅 DESCRIPTION 💅

okay so the ptm driver is the backend for the /dev/ptm device, and it supports three ioctl(2)s. The first is TIOCPTMGET — it allocates a free pseudo-terminal device, sets its user ID to the calling user, revoke(2)s it, and returns the opened file descriptors for both the master and the slave pseudo-terminal device to the caller in a struct ptmget. That struct is giving:

struct ptmget {
        int     cfd;
        int     sfd;
        char    cn[PATH_MAX];
        char    sn[PATH_MAX];
};

where cfd and sfd contain the master resp. slave device's file descriptor and cn and sn the corresponding paths in the file system. 💖

The /dev/ptmx device supports two more ioctl(2)s: TIOCGRANTPT, which is used by grantpt(3), and TIOCPTSNAME, which is used by ptsname(3).

The ptm device is included with the pseudo-device pty(4). It can be disabled by adding options NO_DEV_PTM to the kernel configuration.

🎀 FILES 🎀

these are the paths you need to know, bestie:

  • /dev/ptm — ptm access device
  • /dev/ptmx — ptm cloning device, used to implement Unix98 ptys

🌈 SEE ALSO 🌈

go give these a read when you're done slaying:

👑 HISTORY 👑

The /dev/ptm device appeared in OpenBSD 3.5 and was ported to NetBSD 3.0. iconic behavior, honestly. 🔥

💖 and that's the tea: this page comes from Debian, dated November 30, 2013, and it's the PTM(4) manual — mwah, bestie 💖

📦 where this page comes from